The present invention relates to a chassis (i.e., a frame or body or housing) for optical instruments for the permanent, precise holding of components.
In optical instruments, the optical components (e.g. lenses, mirrors, slit members, etc.) must have precisely defined position with respect to each other. This position must be as stable as possible under the action of time and heat in order that the apparatus retains the desired properties for long periods of time and at different surrounding temperatures.
For this reason many chassis of optical instruments are made of metal. In that case, due in part to the structural development and the selection of suitable materials, the influence of temperature is reduced, but this always requires a corresponding expense. Aside from this, due to the internal stresses caused by their manufacture, metal bodies can only at great expense be brought into a condition in which high dimensional stability for long periods of time is achieved.
Recently, bodies or housings of fiberglass-reinforced plastic have become known, particularly for field glasses. The manufacture thereof is, however, expensive. Furthermore, the liberation of gasses as well as aging phenomena have not yet been clarified sufficiently for many purposes of use.
From the manufacture of large mirrors it is known to use glass-ceramic. However, it is so expensive to manufacture that the use thereof does not enter into consideration for series production, that is production in substantial volume. Recently the demands made as to the stability of optical instrument chassis or bodies over a period of time and also thermal stability have increased greatly, due to the introduction of diode arrays, also in series manufacture. In these diode arrays the individual receiver elements have dimensions of only, for instance, 25 .mu.m. In this case the adjustment of a spectrometer which has a diode line as receiver must remain constant within fractions of 25 .mu.m. However, better thermal stability and stability during passage of time would provide advantages also for many other instruments.
Accordingly, the object of the present invention is to create a chassis (i.e., frame or body or housing) for optical instruments which is characterized by particularly good and lasting stability, little influence by heat, and economical manufacture.